Collapsible tap



A. A. SHAFER.

COLLAPSIBLE TAP.

APPLICATION FILED JUNE27, L919.

9 192 300 3 SHEETS-SHEET 1.

Pawmhed July H A. A. SHAFER. COLLAPSIBLEVTAPI APPLICATION FILED JUNE 2? Patented July H mm 3 SHEETSSHEET 2.

H v i A. A. SHAFIEW. COLLAPSIBLETAP.

ICATION FILED JUNE 27,

Pmteme July all 12 3 SHEETS-S & W.

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pening in which a pivot post 0 on the lower end of the central shaft member is journaled as shown in Fig. 1. Preferably the blocks B, side-plates l) and disk G are made of extra hard metal so they will not readily become worn or marred in use.

The ring C is non-rotatably fixed to the annular shoulder E of the central shaft member by means of a key 6 (see Figs.

1 and 7) thereby causing said ring C and central shaft member to rotate in unison, so that the cam E will force the chasers outward at one movement of the central shaft member and while so doing the cams on the ring C (see Fig. 2) move away from the blocks B permitting the outward movement of the chasers F and blocks B, and on the reverse movement of the central shaft memher the cams move away from the chasers and the cam-surfaces on the cam-ring C en gage the blocks B and move said blocks and chasers secured thereto inward.

In the periphery of the ring C I provide a circumferential slot If. in which I place a spring H (seeFig. .6) one end of which engages a post A secured in the wall of the body A; and the other end thereof engages a post 0 secured in the ring C; said spring H being thereby adapted to rotate said ring in one direction.

iifounted upon the portion IE of the central shaft member is an operating ring J in which a hand lever J is secured which projects outwardly through the slot a in the wall of the body member A.

In the upper surfaces of the ring C I provide a diagonal slot K, which I preferably make slightly curved as shown in Fig. 7 and in the lower face of the ring J I provide a radial slot J in which I place a slide J which has a projection J which enters the diagonal slot K in the ring C. To operate the slide J I provide an adjusting screw J 5 the ends of which respectively engage the central shaft member E and the inner wall of the body member A (see Fig. 1) said screw passing through said slide J To give access to said screw J 5 when the mechanism is in the position shown in Fig. 1, I provide an opening 'in the wall of the body member A. By turning said screw so as to move the slide J radially in the ring J the projection J traveling in the diagonal slot K in the ring C will cause said ring C to rotate with. relation to the ring J, thereby adjusting the throw of the cams E on the lower end of the central shaft member.

Slidably placed in the upper end of the body member A is a shank-hub L, (see Fig. l) which is provided with an annular shoulder L of reduced diameter. Between the periphery of the hub L and the inner surface of the body A I bore a plurality of holes,

preferably three equally spaced, half of each hole being in said hub and half in the wall of the body member, in which l place driving keys, or rods M (see Fig. '1) which ('(llllpel joint rotary movement of the body A and hub L. To maintain the hub l1 normally in contact with the ring J as shown in Fig. 1, I provide springs N, preferably two equally spaced, and located in holes, as provided for the keys M, one-half in the hub and half in the body and to secure the keys M and. springs N in place, and also to prevent the hub L from being withdrawn from the body A, I secure a ring on the upper end. of the body member A by means of screws O.

P indicates a shank screwed into the hub L. To lock the ring J in position shown in Fig. l, which is the tln'cad-cntting position of the tap, and in which the spring H is compressed, I provide a bolt It which is placed in a recess R in the hub L and seoured therein by means of a threaded bushing R and is provided with a. spring It to maintain it in locked position. The bolt R enters a recess in the ring J and locks it in the position shown in Fig. 1.

In operation the hand lever is used to turn the ring J into the position shown, which through the adjusting slide .l turns the ring 0 a d central shaft member Illfi in unison therewith and compres es the spring H until the locking bolt ll enters the recess in the ring J, which locks the mechanism and maintains the chasers in expanded position as shown. When the chasers F have reached the limit of their cut, the tap is forcibly moved backward from the work which causes a longitudinal movement of the shank-lull.) L away from the ring J, and draws the locking-pin R out of the recess in the ring J, which releases the ring J so that it and the ring C can be operated backward by the spring H, to collapse the chasers and allow the tap to be withdrawn from the work without the necessity of unscrewing out of the work.

Having thus fully shown and described my invention so that the same an be utilized by others, what I claim as new and desire to secure by Lettersdatent is:

1. In a collapsible tap a body member having radial slots, chasers slidably mounted in said slots, a central shaft member in said body, cam surfaces carried thereby adapted to force said chasers outwardly at one movement, and the cam ring mounted thereon and rotatable with said central shaft to force said chasers inwardly at the reverse movement thereof, substantially as described.

2. In a collapsible tap, a body member having radial slots, chasers slidably mounted in said slots, a central shaft member, cam surfaces thereon adapted to move said lll lli

realistic said shaft member, means to adjustably connect the same with the first mentioned ring, a. shank hub slidably and non-rtatably mounted in said body member, a spr ng messed: locking bolt carried thereby and adapted to enter a recess in said operating ring when it has been rotated to its limit in one direction, substantially as set forth.

3. ln a collapsible tap, a body member having radial slots, chasers mounted in said slots, rotary cam mechanism adapted to move said chasers outward and inward, a

diagonal slot in said cam mechanism, an

operating ring, a radial slot therein, a slide in said radial slot and projecting into said diagonal slot in said cam mechanism, an adjusting screw in said slide, a spring to rotate said cam mechanism to closing position, and a hand lever to rotate said operating ring to expanded position, substantially as set forth.

l. .lln acollapsible tap, a body member having radial slots, slidable blocks in said faces thereon adapted to engage said chasers to move them outwardly, a spring actuated ring non rotatably secured on said shaftmember, cam surfaces thereon adapted to engage said slidable blocks to move them inwardly when said ring is actuated by its spring, an operating ring on said shaft-memher, a lever to operate the same in one direction, adjustable means to connect said spring-pressed ring and said operating ring, and means to locl: said operating ring, substantially as set forth.

5. ln a collapsible tap, a body member having radial slots in one end thereof, and a cylindrical chamber therein communicating with said slots, and an integral ring a l? bridging the inner ends of said slots, substantially as set forth.

6. In a collapsible tap, a body-member .havin radial slots in one end thereof chasb 7 ers mounted therein, rotatable cam mechanism centrally mounted in said body member adapted to move said chasers outwardly and rotatable cam mechanism to move said Chasers inwardly a hand lever to rotate said cam mechanism outwardly, and spring mechanism to move the same in the opposite direction, a shank non-rotatably and slidebly mounted in said body-member, means to yieldingly maintain the samein its innermost position, and a spring-pressed locking bolt carried thereby to maintain said cam mechanism in' position to expand said chasers, substantially as described.

In testimony whereof I allix my signature.

' ARTHUR A. SHAIFER. 

